Along with the prevailing resinification of automobile fuel tanks, resinification of various fuel parts attached to the fuel tanks are being contemplated, for which resins superior in gasoline barrier properties, such as fluororesin, ethylene vinyl alcohol resin, polyamide resin and the like, are attracting much attention. Of these, one of the most promising candidates, nylon 12 resin, has been developed for use as a material for fuel parts.
However, the gasoline barrier property of nylon 12 resin is poor as compared to numerous other polyamide resin groups and nylon 12 is not entirely sufficient as a material for fuel parts. In addition, to improve responsibility for safety required of fuel parts, a laminate thereof with a polyethylene resin used for fuel tanks is under investigation. However, nylon 12 resin has poor heat seal property with polyethylene resin, and fuel parts obtained by forming the laminate show strikingly degraded adhesion strength of the heat seal surface after immersion in gasoline for a long time, which in turn causes decreased strength and stiffness.